Method of fluid mining



Feb. 4, 1958 w. c. BRINTON 4 2,822,158.

METHOD oF FLUID MINING Filed March 5. 1949 io sheets-'sheet 1 fag;

85 63;; @www Feb. 4, 1958 w. c. BRINTON 2,822,158

METHOD oF FLUID MINING Filed March 5, 1949 l0 N v500 l0 Sheets-Sheet 2 IN V500 @n Feb. 4,1958 w. c. BRINTON 2,822,158

METHOD oF FLUID MINING Filed March 5. 1949 1o sheets-sheet 5 Feb. 4,1958 w. c. BRINTON METHOD oF FLUID MINING 1o sheets-sheet 4 Filed March5, 1949 @any ya Feb. 4, 1958 w. c. BRINTON METHOD 0F FLUID MINING' 1'0sheets-sheet 5 Filed March 5, 1949 Feb. 4, 1958 w. c. BRlNToN METHOD OFFLUID MINING l0 Sheets-Sheet 6 Filed March 5, 1949 l?? 067e for award C/"z'n of? Hvmii F eb. 4, 1958 Filed March 5, 1949 '111111111114- '1-l1lll/1121lll/11111111111111111111 W. C. BRINTON METHOD OF FLUID MINING10 Sheets-Sheet 7 Feb. 4, 1958 w. c. BRINTON 2,322,158

METHOD OF FLUID MINING Filed March 5. 1949 10 Sheets-Sheet 8 Feb. 4,1958 w. c. BRINToN METHOD oF FLUID MINING' 1 0 Sheets-Sheet 9 FiledMarch 5. 1949 Feb. 4, 1958 w. c. BRINToN 2,822,158

METHOD OF FLUID MINING Filed Marh 51949 t l0 Sheets-Sheet 10 WZQLB/ 22,/j?? 32' 22/ 'lfzo? [Il i LBJ 7e L' efe fw Unit@ This invention relatesto methods for mining by the use of fluids under pressure. It isparticularly directed to the extraction of valuessfound in strata atsuch distances below the surface of the earth that it is more economicalto extract the values by means of deep wells or bore holes than by theuse of shafts large enough to permit miners to go down into the mine.The strata containing the values frequently extend under large areas ofthe earths surface and it is desirable to sink as few wells as possible,and therefore, as large an area should be mined from each well as can bedone.

The present invention is particularly applicable to the mining ofsoluble deposits, such as salt, potash, and particularly trona, such,for example, as thatv found in the State of Wyoming. The invention inmany of its aspects is also applicable to the mining orwextraction ofvalues from deposits of more or less loose granular or friable material,such as oil-hearing sands, in which the oil may be extracted by solventsor washed out with hot water or other suitable liquid vehicles. Indealing with such soluble or loose materials, special problems areencountered differing from those which are met with in mining ordrilling through rock formations which are of a self-sustainingcharacter. For example, in a deposit of salt or other strictly solublematerial, it is important to form the underground workings and apply thesolvents in such manner as to continuously bring the solvent intocontact with the material to be mined in themost ellcient manner. Caremust be taken to avoid premature collapsing of the roof of thesubterranean cavity, thereby blocking proper flow of the solvents andslowing up the action. In the case of materials which are wholly orpartly insolub1e,.only a certain proportioning of the deposit beingvaluable, as in the case, for example, of oil-bearing sands, it isdesirable to extract the oil while leaving the worthless part of thematerial, such as the sand, in the ground; thus to make it unnecessaryto lift to the surface large volumes of waste material.

In accordance with the present invention, a well or bore is drilleddownward until it reaches the stratum to be mined. This well may bedrilled and cased in accordance with usual well drilling practices. Inorder to mine as large an area as possible from a single well, a pipe orpipes are then passed down the well, the pipe or at least the lower partthereof being of such llexibility that it may be caused to bendlaterally so that it may be progressively advanced in the general planeof the stratum to substantial distances from the axis of the well. Thisis accomplished by providing a pipe which may be termed a probing pipe,or a pipe with a probing nozzle at its end. Such pipe must have suicientstitness so that it can be pushed downwardly and outwardly, the solventbeing at the same time forced through it so as to open a passage for thenozzle as the noule is advanced. The pipe must have a suflicient degreeof rigidity'to. enable it to beso advanced, and it must also haveacertain amount of flexibility in at least one plane passing througharent or even in a single radial direction.

the axis of the pipe to enable it to follow the plane of the stratum andtherefore to bend more or less in a direction at right angles to theaxis of the well or bore. With such a pipe forced from above andsimultaneously feeding the solvent or erosive liquid to the end of thelateral hole which it is forming, the probing nozzle may be advanced togreat distances, perhaps a matter of hundreds, or even thousands offeet, from the axis of the bore. In general, the greater the dip of thestratum, the greater the distance the probing nozzle may be advanced.

It is not sufficient, however, merely to be able to advance the probingnozzle in a haphazard lateral direction The invention, therefore,contemplates controlling the direction of lateral advance of the probingnozzle. This is preferably accomplished by utilizing a pipe which, whilehaving sullcient llexibility in one axial plane to permit the pipe tofollow the direction of the stratum, has sufficient rigidity in a secondaxial plane at right angles to said first axial plane to enable it toresist. deviation to the right or left of a desired radial path which itis intended that the probing nozzle shall take.'v Various ways ofvproviding a pipe having the desired llexibility and stiffnesscharacteristics are within the scope of the invention. For example,commercial llexible metal pipe may be utilized. As such pipe is equallyflexible in all directions, means are provided for rendering itresistant to llexure, except in one axial plane. This 4may 'beaccomplished by attaching to the pipe a flat strip of steel which willbend with the pipe to permit it to advance parallel to the stratum butwhich will resist bending in an axial plane at right angles to the axialplane of the bending. Such a pipe, thered fore, may oe forced down andcaused to bend into the plane of the stratum and pushed out radiallywithout deviating substantially from a predetermined radial direction.

Such a strip of steel also performs other important functions. It servesas a skid or ski providing a surface which will facilitate the outwardmovement of the pipe in the plane of the strata. It also assists insupporting the weight of the flexible pipe sections. In a deep well,

obviously, many sections of pipe are required which must together withsuitable couplings.

be coupled together, and the weight of the column may be such that thetensile strength of the pipe is insuflicient to support the column.mercial flexible pipe of the helically wound type is used, theconvolutions of the pipe may be either wholly pulled apart or separatedsulliciently to permit leakage. If the pipe is anchored to the steelstrip at intervals, as, for example, at each coupling, then each pipesection only has to sustain its own weight which is transferred throughthe coupling to the long steel strip. This permits the use of a columnof any required number of pipe sections, as the steelstrip may be madeof such section as to provide the `necessary tensile strength forsupporting the entire column.

Another type of tubing having similar bending characteristics consistsof a steel tube or pipe which is partially flattened so as to give it agenerally attened or elliptical cross-section. Such a pipe will bendwithout difficulty in an axial plane passing through the minor axis ofthe ellipse but will be substantially rigid or resistant to bending inan axial plane passing through the major axis of the ellipse. Suchatteued or elliptical pipe may be formed into a nozzle at its end or anysuitable nozzle attached thereto, and it may be formed in sections whichmay be weldedttogether as the pipe is advanced down the well, or thesections may be secured In particular, the pipe couplings ofconventional type maybe utilized.

For example, if ordinary comfangen as It is ordinarily not suilicient toprovide a probing pipe which may be advanced only in -a single radialdirection. The pipe should be successively advanced in a plurality ofspaced radial directions Aso as,to reach large areas surrounding thecentral Well, andin order to accomplish this-result, the inventionprovides-means for indexing the probing pipe so that it may besuccessively advanced in different-predeterminedradial paths. This maybe laccomplished'fby use `of'an indexingftube extending down the Well`between the casing and the flex'- ible pipe. The indexingmay beaccomplished by turning'the indexing tube throughdetinite angles, asindicatedby a compass dial at the top of the Well. However, Vas in adeep shaft the -tube may twist yvery substantially between the upper.'and lower j endsthereof, such twist amounting in some 'instancestoseveral complete revolutions, it is diiiicult'4 to determine the trueorientation' ofthe probing nozzle by' adjusting theangle of theindex'tube. at its upperend. The'invention therefore contemplates theprovision 'of lmeans for'determining the orientation of the lower endof'the indexing tube and then utilizing means at'the lower end of'saidtube for determining the orientation of the iexible pipe and probingnozzle. `In this way, the radial direction of the passages orptunnelsextending from the' central well may bedeiinitely and positivelycontrolled. Such deniteand positive control not only insures'that valldesired portions ,of the strata may be attacked; but also permitsspacesto ybe left between the laterally formed andthe ilexible pipe andprobing nozzle are caused to form a passage in the'lowest portion of thesoluble stratum so that the probing nozzle may actually be directedoutwardly along rthe upper surface of the floor stratum. Theinventionprovidcs for the accomplishment of this purpose by using. pipehaving tlexibility characteristics which cause it totravel along thesurface of the Hoor stratum. 'For example, if Vthe flexible vpipe isprovided. with a flat steel .plate attached to. it as -described, suchsteel plate'may have sutlcientresiliency.

--very substantial distancesv from oneanother.

extending cavity is preserved and the roof material does rnot tendv to`collapseY near'the centralH bore, whichwonld' interfere with continuedoperation at substantial distances from such bore.

As above stated, my invention is particularly applicable to operationsinvolving the use of deep drilled wells which are of comparatively smalldiameter. The probing pipe is passed down sucha well, or if an indexingtube is used, it is passed down through the indexing tube and therelative diameters of vthe well, or tube, if used, and oftheprobingpipe, are such thatthe probing pipe receives substantial lateralsupport fromthe well casing or'tube; This' prevents 'the vertical partof the probing pipe from` bendingk or buckling to the point of collapse.The walls of the laterally extending passages or tunnels formed by theadvance of the probing pipe may also be -used to provide a similarsupport against buckling of the laterally extendingpart of. the probingpipe. .This isparticularlytrue where'conditions .permitof"a1"apid.advance ofthe probing pipe which can be forcedftoconsiderable distances before theY tunnel is enlarged' by the flow ofVVthereturning solvent liquid to a degree where'substantial supportagainst buckling is no longer provided.

yThe fact that the present invention 'provides a way in which lateralchannels or tunnels Ymay be formed which extendida predetermineddirectionl froml the well, makes itlpo'ssible to link up aseries ofwells which may be at By driving'directional channels-from each ofr suchwells, they may 'stilllbefbroughtinto communication so that one welllrn'ay be used forl introduction of the solvent andl theconnected'wellluse'd'for withdrawal of the brine. In

"'this? Way, thesol'veht may lie-'caused to tlow through considerab'ledistances indirect'contact'with the material to bedissolved',Y therebyproducing Va very effective' action in extracting the "mineralstobe'recovered.V When such a system-is" established,V it is unnecessaryto maintain a to tend to straighten out andtherebyV to. be bent only" tothe extent to which it is deectedjby contact withthe tloor stratum. Thesteel platein"that`case, acts as a sort of ski, sliding on the`surfaceofAthe floor stratum and guiding the probing nozzle soithat vit' forms achannel or tunnel in the bottom ofthe 'soluble'stratum The same resultis accomplished where the elliptical or vflattened pipe is used,suchlla'ttenedfpipe having' a natural resiliency urging it downwardly sothatit 'Willslide along the surface of the floor. stratum.

The formation of the 4initial lateral channels ortunnels'atthe bottom ofthe soluble stratum is an important feature of the invention,as.it"enables the solvent 'or extracting liquid to operatemosteicientl'y. 'The' fresh solvent issuing from the end of' the probingnozzle at`" Thus, conditions for rapidladvancemehtof the'lolve'nt'faction isY "hydrostatic head throughoutthe undergroundworkings,

so that the workingsd-o not* have to be filled with the solvent.- Thisgreatly reducesthe quantity of solvent Which'fis required, Vthis beingan important featurel where water offsuitable'purity is scarce, or wherea non-aqueous solventlor-a solvent containing special reagents is ern`ploy'ed; lIt-is alsoimportantwhere use of a hot solvent or-liquidvehicleis'fdesira'ble, because there is a smaller volurne-y o'f'- liquid yvtocbeernaintained at temperature and theter'nperaturesemay' be verymuchmore 'easily and accuratelyJ controlled.

In theliartoffmining'by aqueous solvents, the'practiceissometinresf-follewed-ofpassing air with the "aqueoussolventiinto-alarga:J cavibflor'pool in the `deposit* at the,.bottom'offlthelshaft. fThefunction-of the air is' to prevent`Vthen-solvent!from*contacting and weakening the roof of thezformedcavity'until such time as the'cavity has been enlarged laterally as faras practicable. Thismethodof mininglhasfoundapplication in obtainingsodium chloride` fromsubterraneanfdeposits yand has been suited for the'purposerbecausel'of they great thickness lof" the deposits. Inu'myinventiomonthe other hand, I vhave greatly extendcdtheiapplicability ofsuch-a process by enabling air toibeflusedf. efiectively'fin connectionlwithA the working ofitliinrstrata.v IM3/invention contemplatesthe'use,'where 'necessarypoff compressed air, either introduced in' thesolvent'liquid.lorLseparately-fsupplied, soas to keep down the level'offthen` solvent in the-lateral cavities, thereby reducingtheqantity-offsolventin theworkings and protecting:.thefroofs'ofthecavities from undueweakening. 'The' use of'fair4'infthismanner isnotalways required, but'may be Aemployed in some instances,^particularlywherehigh'ly solublefmateriaL'such assaltg'is'being mined.

In* sornenstances," other `inert gases than air may' be use d. "Tlreterm air as 'used herein, is intended to in- 'cluclefatrty"such'inertjgaa ItA is also possible under some connitionsato useinfiziertliquidA l'ighter-'thantheaqueous solvent to prevent the solventfrom contacting the roof of the cavity. Such inert liquid should oat onthe surface of the solvent and should be of such nature as not to form agummy or other deposit on the surface of the soluble material whichwould prevent effective action of the solvent liquid `thereon.where suchaction is desired. Examples of liquids which are suitable under certainconditions, are light petroleum distillates.

The introduction of air with the solventliquid, particularly wherepressure is used,.is important in my invention where the stream ofliquid and air is directed by a probing pipe or nozzle against the wallof the material to be mined, particularly against the lateral wall atlthe end of a transverse bore or tunnel. The air released at the end ofsuch probing pipe or nozzle agitates the liquid and surrounding materialin course of removal from the wall and promotes the release of suchmaterial and its solution in the solvent if it is solublematerial. Theair assists the jet of liquid in preventing concentration of thesolution in the vicinity of the nozzle from reaching a saturation pointwhere the solvent action is decreased. My invention also contemplatesthe introduction of air under pressure into the liquid intermittently sothat it will be discharged in bursts, thereby producing a greateragitation or eX- plosive effect.

As the strength of the solution increases adjacent to -theend of theprobing pipe or nozzle, any air which may be dissolved in the solventliquid will tend to be released, and if conditions are more or lessquiescent, it may accumulate in small bubbles, so as -to form a sort oflm or protective covering over the face of the working. This interfereswith the direct contact of the solvent with the material to be dissolvedand decreases the rate of solution or erosion. The introduction ofsubstantial quantities of undissolvedair with the liquid, particularlyif such air is introduced intermittently, as described above, serves,with the flow ofthe liquid itself, to displace the film which may beformed and ensure that the surface of the working shall be eiposed tothe full solvent action.

My invention is also concerned with an improved method of recoveringvalues from comparatively thin strata by providing a plurality ofcommunicating holes or bores leading thereto, at least one of whichbores is inclined. In so proceeding, the first hole is drilledcomparatively vertically thereby to locate the stratum, and then at asuitable distance therefrom a second hole is drilled in a directioninclined or curving toward the intersection of a stratum and said firsthole. By enlarging the cavity at the intersection with the stratum ofthe rst drill hole, if necessary, and by employing known directionaldrilling methods for the second hole, communication may be establishedbetween the two holes through the stratum without difficulty. Suchinclined hole has the advantage that its angle of intersection with thestratum is much less than a right angle. This enables a into thestratum, and to follow the same along the iioorA thereof until theregion of the rst hole is reached and beyond such point, if desired.This having been done, the removal `of the material may be accomplishedby feeding the solvent through the probing pipe and removing it througheither the vertical or inclined hole.

It is also -a 4further object of my invention to take advantage ofcomparatively thin sloping strata to cause the solvent to enter thestratum at a high point therein and to be removed from a lower pointladen with the material to be recovered, such gravity flow causingprogressive removal of the material to be recovered. My invention asoutlined above is also readily adapted for mining material occurring instrata which may be strongly inclined to the horizontal.

Other objects and advantages of the invention will lapy pear in thecourse of the Ifollowing description of certain preferred embodiments ofthe invention chosen to illusthe mechanism in Fig. l;

Fig. 4 is a vertical section taken at line 4-4 of Fig. 3;

Fig. 5 is a vvertical section taken atv line 5-5 of Fig. 3;

Fig. 6 is a vertical section taken at line 6-6 of Fig. 4;

Fig..7 is a vertical sectional view on an enlarged scale through thelower portion of the indexing pipe, showing the ilexible tube member Iinposition;

Fig. 8 is a transverse section taken at line 8-8 of Fig. 7;

Fig. 9v is a view in developed-forml of part of the lower end of themechanism shown in Fig. 7;

Fig. 10 is a vertical section on a further enlarged scale, showing ajoint between two flexible pipe sections;

Fig. l1 is a transverse section taken at line 11-11 of Fig. l0; v f

Fig. .12 is a view in vertical section similar to the lower portion ofFig. 1, but illustrating the operation in an inclined stratum whenthetool is moving downwardly;

Fig. 413 illustrates the operation of Fig. 12 after the downwardlyinclined portion of the stratum has been worked as far as desired andwhen means have been taken to cause the tool to move upwardly;

Fig. 14 is a view similar to Figs. 12 and 13, showing two wellsconnected-to the same' inclined stratum;

Fig. 15 is a vertical section illustrating a modied form of pipeconstruction;

Fig. 16 is an enlarged transverse sectional detail illustrating the pipe'of Fig. 15, taken at line 32a-33 of Fig. 20;

Fig. 17 is a further sectional detail taken :at line 34 34 of Fig. 20;

tions of the pipe withdrawn into the casing;

Fig. 19 is a section similar to Fig. 18, -but taken on a plane at anangle of 90 at line 36-36 of Fig. 18;

Fig. 20 is a sectional detail of the construction shown in Figs. 15, 18and 19, with the members lowered partially from the position of Figs. 18and 19;

Fig. 21 is a longitudinal section illustrating a further modilication,particularly of the means for joining the pipe sections;

Fig. 22 is a transverse section taken on an enlarged scale at line 39-39of Fig. 21, illustrating the guiding means;

Fig. 23 is a longitudinal sectional detail illustrating the weldingmeans for joining pipe sections, taken at line 40-40 o-f Fig. 21;

Fig. 24 is a plan view with diagrammatic illustration of the operationof a modified method;

Fig. 25 is a vertical section taken on line 46-46 of Fig. 1;

Fig. 26 is a vertical section on an enlarged scale showing one stage ofthe operation;

Fig. 27 is a horizontal section taken on line 48-48 of Fig. 25;

Fig. 28 is a vertical section taken on line 49-49 of Fig. 26;

Fig. 29 is Ia vertical section taken on line 50-50 of Fig. 24;

Fig. 30 is a vertical section taken Aon line 51-51 of Fig. 24;

Fig. 31 is a vertical section showing one stage of the method applied toa relatively thick stratum;

Fig. 32 is a generally Vvertical section showing another stage of theoperation of the same stratum; and

@seagreen Etigv3timeWerticakaectionshovvingltlletoperatiornofaKsubmerged pump in the Verticaiiholez.

nrgeneral-ittheripparatus;usedznomprisescarmechanism for supplying:tdiwhihi'may belafsolnentzorza :vehicle ont a; pressureimedium. .imagstratum :below lthefsu'rface; of the earth. The device is thereforeassociated.. With a drilled wellomholeand .with almere forlesssconnentional liner for that hole. The meansfondntrbducingnthezd-issolvingior. cuttingatiuid .includesvafdexibleiitubularemember which is lowered into theboreshleritoizthexdesiredfi depthorop'eration. on .the :selectedstratum:r.. uSomef. means is; -`prrnfided forzraising; the; snspended .materialironnthe stratum: to aeolle'etionf-meanse .;.The:;a`pparatus showngenerellysinligures: l. toedY comprises .fsuclna meenam-nas shown in;those tigures,.a safellll 4has'ineensdnilledljnm..the earth passingthroughvvaniousi:Strataauntilnthettdesired stratum to heminedis=reached... l: lhis'stratumfis indicated byg-.the mumeralfZ...'lihe.istra tum.f 2. restsfupon; a floor stratum 3 of shaleonupdesiredxsmateriaLWhichcmay` be. relatively solid or insoluble. The.word -zsalt'ihas .been applied tothestratum Ziandsisrnotflimitediinitsmeaning to sodium chloride, butis ,torhertakenr'generallyiasimeaning anymaterial which can be dissolved by a suitable solvent or. attacked by.afdiuid.mediumoandnwhich Ait .is desi-red to recover. i4-\,isaltubular\ welllining. or. casingV xed in: position within.thebore.,l1ole. -..;Such.;a .lineri will bemade of asmanwsections,of=tubiug.for,casing as` necessary. Attheupper partotthe-hole or bore, ifcdesired, anouter ca sipg may-beplaced In theparticular form: .herewshownyraminnerx tubular member Drfindexing tube??6.is-.inserted.inx.the well; casing and it` is movablymounted,-beinguspended oma support 7 which. is: fadjustably carried. byzfmeans.ofvjacks "8 upon an indexing table 9. This table, as shown in Figs.land 2, .iszsupportedl on anti-friction :bearings ,-10.l The bearingsare-themselves supported.. upon a.-foundati'orrli` within a house orhousingilzadjacenta tank 13 within which the material raised from theWell may be deposited. The table 9 may be indexed: by any. 'desiredmechanismand since such. indexing Imechanisms :are vwell known, nospecific mechanism. is.- shown herewith.

A flexible pipe 14 thecorrect constructionof which will be. describedbelow,isinserted`within thel indexing tube 6-wthin .the .welL constantmeans for guiding'the pipe intoor. out vof thefwell comprisesa `wheel*iSscarried in suitable bearings 16on:.a.support 17. ,The wheel. 15should-be of.: suicient,..diameter so4 vthat Vthe lsomewhat exible.:pipe may, v.pass over e vvit `.without y being.A stressed beyond itselastic limit. A support or tracl.18'is ,pro

vided which may extend .from a ,point close-.tofthef wheel asshowninlFigure i 1, laterally from .them/heel, for any desireddistance. Thesections of the pipe 14 may be made up into.a string of anydesired4length .ons this .support, and the stringfthenfguide'd'.overthe wheellSand down into the' Well. When the pipe-is withdrawn from the well, itcan be pulled backover ,the'supportdS and the sections/disconnected as,desired. Asuita'bielength of flexible pipe is used',Adependent#\upon"'the"depth of the Well and--thefdistance toWhichif-thef-lateraldunnel or probing is to be carried out.

Thenen'd: ofstherexible :pipe: supportedionzlthe asnpport 18 may besecured to an arrangement.ojointedepipes 19-whicl1y `at Atheir outerend-a-reconnected .to-fa fixed system of piping 20. A block 2l carriesthe connection between the exible member 14 and-the, pipesystem'l and ismounted in a track 22. A cable or other raising and lowering means23a-is joined to the .bloclc Z1-,passes about sheaves 24 'andissecured'to a drum 25 "driven by any desired means. 'I he drummaybedriven to raise and lower the'exiblepipe' 14 up and downwithin the. borehole. The system ofpjointed pipes 1,9 provides aconnection fromtheiixed-syst'emj ofpip'ing "29' to* the end "ofethe pipe 14, permittingpressure to'fb'e-supplied'continuously toethetpipes'lnriwhilefitfis-beingfadyaneed down the-well and laterallyhthzerenzateitsdour end..

As showutinfFig.;1;;,the; spacepbetweenutheliner 4:'an'd';

meter 31 is connectedlthrough-.the pipe.32.tothe.tank.

28....- A-. .gauge.- 3.3.cmay .be communication :with lthe j pipe; 32,:andrthe valve,-34. is. also vincommunication. with the pipe 32 and.maybe used afonadjustment.

As abovestate-dpfluidofusome sort,.and usually. liquid, isadischargedthroughtheutlexible .tube .or piper. 14 ltoiact upon; theamaterial which it sis desired to .remove .fromsthel welland'yasrstatedthisplay. be. a solvent, among `whichwater, various oils,caustic@ soda solution, and other. materials areincluded; Sometimes,also detergentmaterialincludingsodium silicateimay bevused. These mate'-ria1s;may bezusedhot or cold'.and.may be mixed .with air or other.sgasesfor. .vapors.

The. apparatus. shownlis such that it is. effective to convey .into Mthebottom=of:the welli and into contactwith the s material nwhich is .to beremoved `whatever huidl .substance .ors'mixtures rif-.fluidi substancesaredesired. For this purpose a pump 35 driven by a motor-36 is used. Theliquid'inlet 37f-of fthel'pump maybe connectcdto any-'fsource oflliquidsupply. A gauge 38 and a safetyA valveSSSa areinfcommunicationwwith thedischarge from the. pump,andf liquid asit movesromthe pump, passes through al system' ofpiping or conduit system 39 toan injector or; mixer-40.

A valve541may-be fpositionedin -theliquid line. i Air moving fromthe'tank 28I through the 'pipe system 32 and 'ithef-airfwfmeter 31`reachesithe mixer or injector 40 through conduit or pipeldZ. The mixer46 is connected to 1thepipe vsystem '20fwhich, IthroughI themovable`pipe systeml--yisconnected to theilirxibley pipe or -tube` 14. Thusliquid `or fgas,-or-amixture YofY them, may bedelivered to the pipe`system'2lb-and thence conveyed' into the well. A discharge-or outletmeans 43 -is connected to the dischargeaside of the pump and isprovidedwith a valve 44. Thus, ifVv a constant capacitypump is used and-itis runat constant speed, the actual liquiddischarge into the system` may bevaried by setting the valve 44 to any desiredpoint. 'Also the pressureon the liquid system'can be ascertained by inspection of the gauge 38.Several valvesare shown in communication with the pipe 29. if desired,the jointed pipe sections- 19 which comprise in effect a pantograph'maybe omitted, and a .exible tube maybe used to connect the water'supplythrough one of -the'valves 45 to the exible tube 14 and the blo'ckorcross -l1ead 21. If desired, valves 45 might be spaced, for example,every fifty feet in the water feed linev 20, andthus a'relatively shortlink of exible tubing .couldbe used for joining the water supply 'tothepipe from the pipe together with the terminal probing nozzle p :1 or'otherdevice To laccomplish these ends, the following arrangementofparts has been provi-ded:

Theindex'tube `is, provided with a latching or positioning member 46.This member is shown in developed forrn'in' Fig. 9. 'As there shown, itcomprises an uprWardly directedpoint-likel member 47. A ,mating mem'-ber 48de positioned on the-outside-ofa relativelyy short tubular section49. The member 48 is shaped with-al notch 1 or depressioni' 50 which;Y-as -shown particularly in Fig. 9, interiits with the-m'ernber46l anditspoint 47;-- =Wl1en the =fparts arel'- thus'intertttedfrelativeirotation' of gezag-15e 9 the tube and relativedownward' movement of the member `49 is prevented.

The. tubular section 49 is provided with inward-projections 51. As shownin Fig. 8, these sections'extend toward each other and define atracklike portion 52, within which a flexible guiding or back member 53of the exible pipe 14is received. Thus with -the parts engaged, as showngenerally in Fig. l, and in detail in= Figs. 7 and 8, the relativerotation of the exible pipe Within the-tubular member 49 is prevented.At the sameitime, by reason of the interlitting of the members 48 and46, relative rotation of theI tubularsection 49 with respectto the indextube is-prevented. Correspondingly, the entireassembly, including theindex tube6, thetubular-.section 49 and the exible `tub`e 14 and itsassociatedparts may be ro' tated inV any desired direction and to anydesired degree by merely rotating the index tube 6, and 'thedegree ofsuch indexing orrotation can be readily ascertained by comparing theposition of the table-9`with the fixed-l index point 9- associated withit, as shown in Fig..2.

Themember 53, which is a at exible band of steel or other metal, servesas a guide and support for the pipe l14 and provides in a sense a skirunner whichy supports and guides -the pipe 14. This exiblemember may.be given an initial bend for the lower portion of'its length,for eXample, for the'lower'five feet. The bendis suicient to causeit and thepipe 14 to spring somewhat sideways and thus to tend to move toward a`horizontal position when freed from the indexing tube, even without theaction ofthe supporting post 63. The flat strip 53.is at-- tached to thepipe 14 in substantially tangential relationship. Thus, the strip willbend with the pipe in one direction but will resist bending in adirection edgewise of the .'strip.. Thus, the pipe and strip may bend ina more orless .horizontal directionA at the bottom of the well so astofollow the vplane of the stratum, but owing to the resistance of the4stripto' bending in a transverse or edge- Wisedirection, the'pipe willmaintain a radial direction as it is advanced laterally from the bottomkof the Well. Thisis important in connection with the indexing meansdescribed and enables the path which the pipewill take to be accuratelycontrolled.

By means of the arrangement described,--pipe 14 and the attached strip53 may be removed fromthe well,` in which.' case the member 48 bearingVthe-interlttingportion47 will be carried upwardly by reason offthefactthat' the pipeend will be larger than the netarea of the bore.- When thepipe end is replaced, the members 46, 47, 48`will be carried down intothe tube 6 again andthe partswill intert as indicated in Fig. 9, therebyorientingz.

the end of the pipe 14. A feature of the intertting parts. 46, 47, 4S isthe straight sided portion 48a which prevents the lupper portion 4S fromridingup upon: the portions 46, 47, when the index tube 6 is turned.`

In` practice the position in azimuth of the key'46, 47 willV beascertained by methods Well known in the art of welll surveying, wherebythe desired relation of the intertting part 48 to the intended nozzledirection is had prior to', the introduction of the probing pipe-14.- Inthis manner, the operator is aware at all times of the direction of the.tunnels which are to be made beneath the ground.

The diagrammatic showing of the conditions which prevail in the wells orbores in which the device-and methods areto be used has been simplifiedand it is to be understood that a well of any substantial depth willynotV be straight. Inevitably such wells deviate from the verticalsubstantially and repeatedly. This lwell casing, the indexing tube andthe exible pipe will, therefore, not in normal conditions of operationbe centered and symmetrically `arranged as shown. some degree bent andout of center, and one member will bear on the other. The showing is,therefore, intended to be simplilied in this respect.

Also, it is to be understood that the 'indexing tube will notbe made inasingle unit, butwill be made of sections Inevitably, they willbetowhichy are'coupled together." These sections mayib'efprovided withyantifrictiombearings` to simplify the -indexing and to reduce thefriction which would otherwise be present when the more or less bentindexingA tube vis rotated or indexed in the more or less bent wellcasing.` Itfis, therefore, within the contemplation ofi the inventionvtoprovide means for overcoming friction both in raisingand loweringtheindexing tube and the exible pipe andto overcome .ffriction-Y when`these members are rotated -v ytor indexed.

The iiexible tube-.or' probing pipe 14 is not conveniently made'inonempieee t `ofvsufricient length to extend :to the bottom-of awell.lHence,it is ordinarily made -in-afnumber..of-lengths-.and-these .lengths-must bejoined.A As shown-in-Figf 10; twolengths have .been joinedvorlfcoupled.. For this :purpose a nipple 54 is inserted .withnan end-ineach .of two: adjoining pipesections 14.l A raised external-portionSSV-'isa preferably formed. centrally ofl and integrallywviththemember54.A The member 55 .maybe grooved .externallyas-.at 56. A 'sleeve 57 .ispositioned over .the-adjacent .ends.of.the members 14 and overlies allor a portion of-.the nipple 54. It is compressed inwardly bythe.formationsofagrooves 58.. As these grooves are formed theycause thesection` below them tobe compressed inwardly somewhat and thus to grip.the portions of themembers 14,*which they overlie, and to hold. themtightly. against the nipple- 54.

The strip53 above referred to maybe of a singlethicknesso-r of severalthicknesses, and the pipe 14 -is` fastened to it. If desired,the sleeves57, where theyare in position; may be welded as at 60 in Fig'll to themember. As shown in Figs. l0 and 1l, the member 53 is formed of twothicknesses of material, 53 and 53a.' Theuse of twothicknesses serves,among otherpurposes, to .pro-

.vide a means for joining lengths together.. ...Th i,1stw`o lengths ofthe member 53, as shown in Fig. 1,0,V`are welded together as at 61'andtwolengths of the memb'e'rSvBa are. welded ytogether as 'at 62." The.wel'ds" mayme'r'ely join lengths of thematerial to each other 'ormayg'inaddition, join the two member 53 and '53@"at ,spaced inte'rvals.It will be noted that the coupling sleeves j57'ftr`an'sfer the Weightofthe pipe 14 'tothe :strip'53 so that. only one lengthor unit' of thepipe 14 is' in `tension;

Asishown in Figs."l and 2, the'borepasses'tlirough strata of undesirablematerial untilit'reaches 'a stratum? of desirable material; Thisstratumisnottbf'infinite'depth and-its lower `level 'or' surface 'is'de'ned *by lthe o'o'r stratum 3. For some purposes it is desirabletoprovidea mechanical supporting and guidingmeans for 'thee'xible tubeor probing lpipe 14 `at 'the bottom`of='the,iwell." As shown,"thiscomprises a post 63 .which is set in 'a-depression 64 in'the oorvstratum '3. It may have a rounded'upper end 63a, as shown, and vmay be,held ,inpla'ce by cement or otherwise, if necessary.' The upper 'endoftheip'ost may also -be provided 'with Va groove 63b`to assistin' itswithdrawal, if desired; As the Working tool or `probing nozzle islowered with the flexible pipe 14 it will contact the member 63 and beguided out of a vertical position toward a horizontaly position.' Insome instances,' in order to facilitate the forward feed of the endof"the.ppe 14, the lloorof the cavity maybe covered withsm'a'lL easily`owable discreteparticles, suchas marbles or rounded pebbles 63' feddown the shaft. In size'"they may range from'about 1t'to 1" indiameter,forexample. InFi'gLl the Well has been completed; the member'63 hasbeen'set in position'` and operations may commence. It is to belunderstoodthroughout that the well, .whether in'the'stratum 2 or anyother stratumgmaybe somjewliat irregular in shape and size, beingsubject tol the-variating earth conditions usually encountered in alldrilling. The well is illustrated asl perfectlystraight, for'convenience of illustration. Y

The condition of Fig. 1 is that .which rprevailsievtl-hen operationshave beencarried out: for a.short` whilesl The pipe 14,= with the`worltingftool.l at its lower. end; .has-sheen for the solution asit'leaves the well.

1 1 inserted and some mining operations have been carried out. As shown,the well 1 has been enlarged at its lower end by the creation of thespace-X. 1

As shown in elevation in Fig. l and in plan in Fig. 3,

the probing pipe and nozzle is fed downwardly and outwardly as itremoves the desirable material and thus tunnels or paths 65 are formed.The total is shown in Fig. 3 lying in one of these tunnels or paths,with others already formed. By indexing the assembly which includes theindex tube 6, the member 49 and the exible pipe 14, the probing pipe maybe directed in any direction and the spaces between the tunnels 65 maybe attacked and material removed. Desirably substantially the fulllateral extent of the tunnel may be made while keeping the height of thetunnel substantially constant. This is accomplished by maintaining anair cover over the liquid level, as shown in various gures, the airbeing fed into the cavity along with the solvent liquid or separately.The liquid level will be determined by the position of the lower end ofthe tube 6, and when the desired lateral distance has been reached thetube 6 has been raised to a'higher level as indicated by the dottedlines a-a, b--b, etc. (Fig. l). By so proceeding, the maximum ofthedeposit may be removed without danger of the roof collapsing.

Figures l2 to 14inclu'sive,'illustrate examples of operation on aninclined stratum. Thus undesirable strata 66 lie on each side of adesirable stratum 67 and all of the strata are inclined to thehorizontal. Supporting post 63 is positioned in the same manner as shownin Fig. 1 and serves the same purpose. It furnishes an initial guide forthe tool to turn it'frorn the vertical to or toward a horizontalposition and also supports the pipe 14 at the bend.

As shown in Fig. 13, the lower part of the desirable stratum 67 has beenworked as far as desired and the well 1 has been closed or plugged by asecond support 68 held in place by concrete 69 or otherwise, and byproperly indexing the movable tubular assembly, the tool and .the pipe14 have been caused to move upwardly along the i desirable stratum.

As shown in Fig. 14,` two wells have been used and working has takenplace from each well. The workings or cuttings have ioinedand the exiblepipe 14 has been removed from the lower well so that circulationofliquid or liquid and gas is accomplished by introducing them at one welland withdrawing them through a liexible pipe 14 at another well.

Where a stutling box is required, one is provided. The stutiing boxappears about the indexing tube 6 at the upper end of Fig. l. A modifiedarrangement of stuftng boxes occurs also at the upper right-hand portionof Fig. 14. As shown in that figure, the upper end of the flexible pipe14 is secured to the rigid pipe 14'. Obviously where a deep well isused, it is possible to use a section of rigid pipe for communicationwith the flexible pipe 14. purposes this is desirable-and although it isnot shown in Fig. l, it appears in Fig. 14. As there shown a stutng box142L is positioned about the pipe 14 and seals the space between it andthe indexing tube 6. A second stuiiing box 14o appears in Fig. 14 aboutthe indexing tube 6 and seals the space between it and the fixed wellcasing member 4. This is substantially the same as the stutling boxshown in Fig.` 1. The stuffing box construction of Fig. 14 isparticularly adaptable to the arrangement shown in that igure in whichtwo wells have been connected. The two wells are connected as shown inFig. 14. The admission of the liquid and air mixture of the rst well iscontinued so as to lift the at least partially saturated solventupwardly of the pipe 14 of the second well.

The air introduced along with the solvent is removedy along with thesolution and its presence serves as a lift Other eects may be had,especially that of agitation, the amount of air ladmitted being easilyregulatable by manipulation of For some valve 34. Furthermore, air whichis dissolved in the solvent admitted is released as the lsolventacquires dis- This the stratum at a lower level than the other, and thenafter an underground connection has been established between the wells,the solvent or extraction liquid is forced Idown into the stratumthrough thelower well and drawn out through the upper well. For example,the lower well may be drilled and a solvent liquid introduced and `acavity formed at the bottom of the lower well. The upper `well may thenbe drilled` and a probing pipe 14 forced down from the same into thestratum and a connecting maintained in the underground workings and bymeans lowert well.

channel 67a established between the wells. The probing pipe, if one hasbeen used, may be withdrawn from the Extraction of the values from thestratum 67 may now be carried lon-by|- passing a liquid vehicle down thetube 6 in the.lowe r well and withdrawing it through the pipe 14 intheupper well. Air pressure is of this air pressure and byregulating theelevation of the lower end of the pipe 14, the level of the liquid in-the pool may be controlled.' As shown, the level of the `30.

. above the pool at the -bottom of the lower well. By pullliquid isslightly below the roof 67h of the soluble stratum ing the pipe 14 up alittle way and properly regulating the amount of air inthe working, thelevel of the liquid may be brought up so as to permit the liquid toattack the roof 67b and dissolve or extract material therefrom. Thisprocedure can be continued, gradually raising the i elevation of theroof, as indicated by the horizontal dotted f lines in Fig. 14. In thisway, the entire deposit between .the two 'wells may be removedorextracted. As there ,is :no withdrawal of liquid from the pool throughthe lower well, caving of the roof around the lower well will notinterfere with the continuous discharge of the brine yor liquid bearingthe values to be extracted through the upper well.

. mechanism is shown.`

It will be seen that in a formation such as shown in whichthe stratum ofsoluble material 67 is covered by a -stratum of undesired material, suchas shale, the lower surface of ysuch stratum may be attacked by theliquid 'when ythe level reaches the same, for example, at the region 67=.V Asv the soluble material is gradually removed, more and more of thesurface of this shale stratum may t be exposed to the liquid so that ifsuch material is of a nature'to' be-loosened by the liquid, it may caveinto the pool below the lower well. If such caving takes place to adegree where there might be crushing or flattening of lthe lower end ofthe pipe 6, such pipe can be pulled up i from time to time so `as toprevent injury to it. If necessary, the lower end of the casing 4 canalso be raised by f pulling the casing in a well-known manner. There isno danger of caving of the roofaround the upper well as the liquid iskept well away'therefrom by the air in the workings. There is littledanger of the caving of the roof in the vicinity of the lower'wellaffecting the end of the pipe 14,'as -that is located at a'substantialdistance from the bottom of the lower well and this distance isconstant- 1y increased as the pipe 14 is drawn up. It will be seen onwhich'the nozzle 144 is mounted. The tube 143 has an initial bend sothat it is biased to bend laterally away from the longitudinal axis ofthe casing 4. As shown in Figs. 16, 17 and 20 in particular, the pipesection 141 is guided by guide strips 145 which are weldedor otherwisesecured on the inside of the aligning shield 6. They are positioned toreceive and guide the llattened pipe 141 as shown particularly in Fig.16. The cam sleeve 140 is provided with a threaded collar 146 by meansof which it may be clamped upon the aligning shield 6'. Fixed within thecasing 4 is a guiding and aligning tube 147 which is provided with aninwardly directed rib 148 which is pointed at its upper end, as at 149.The cam member 148 is shaped to provide a slot 150 which is flared orenlarged, as at 151, and the member 140 terminates in a point 152 whichis diametrically opposite the slot 150. The slot is closed orsubstantially restricted, as at 153, to provide a stop for the member148, as indicated in dotted lines in Fig. 19. As shown in Figs. 17, 18and 20, stop blocks 154 are secured to the shield 6' by welding 155, orotherwise. Shield 6 is thus suspended upon the end portion of pipe 141.When the assembly is originally lowered, the parts occupy the positionof Fig. 18 and the coupling 142 is substantially in contact with thestops 154. The parts are held in this position by one or more shear pins156. After the pipe has been lowered to the position of Fig. 20, theshear pins are broken.

The aligning means of the forms shown in Figs. to 20, inclusive,comprise the use of flattened pipes and means within the well casing 4for guiding and orienting such llattened pipes. When the structure is tobe used, the parts occupy initially the position of Fig. 18. In thatposition the parts are held against relative movement by the shear pins156. The shield 6 with the flattened pipes held in fixed position withinit is lowered. When the shield 6 has reached the desired loweredposition of Figs. 15 and 20, its further downward movement is stopped atthis point by the rib 148 which, in combination with the cam member 140and the slot in it, guides and stops the shield 6.

The weight of the pipe sections 141 and 143 and those above them shearsthe pins 156 and the pipe 143 is lowered further and protrudesincreasingly from the well casing 4. Since the pipe 143 has an initialbend or bias, it springs or moves laterally out of the axial plane ofthe shaft, as shown in an initial stage in Fig. 2O and in a later stagein Figs. 15 and 31. Usually fluid is discharged from the nozzle 144 asit commences to emerge from the shield 6 and as the lluid iscontinuously discharged and the pipe 143 emerges further from the shield6', the nozzle works its way laterally as shown particularly in Fig. 15to enlarge the opening formed in the stratum 79,

andnally to move a substantial distance out of axial alignment with theshield.

Ultimately the nozzle 144 passes to the bottom of thesoluble stratum 79and may move widely in a lateral direction. The movement of the nozzlewill be generally the same as the movement of the nozzles shown in theearlier figures; for example, in Figs. 1, 12 to 14, inclusive, andelsewhere.

In the modied form shown in Figs. 21 to 23, inclusive, the constructionof the casing 4 and the shield 6' and the cam member 140 is as describedabove. Changes have, however, been made in the pipes which carry thenozzle and in the aligning or guiding means. For this purpose, guidingplates 157 are secured by welding 158, or otherwise, to the interior ofthe shield 6'. In this form of the device, continuous flattened pipesections 159 are used, at least for the portion destined for lateralextension, and thus the upper pipe section 159 is welded, as at 160,. toa lower section 161. The lower section 161 is itself shaped to provide anozzle portion 162 which may be provided with a forward opening 163 andother or lateral openings 164. Welded or otherwise fixed to the pipesection 161 is a Stop 165.

When the shield 6 is to be raised or lowered, itispositionedfandfsupported'by1the contact of'r the stop 165:-'withthe"-=guide-rnembers'157.y To keep the shield '6' from moving onjitssupportronthe flattened pipe section while-being lowered'into'thewell,shear pins 165" are' preferablyprovided to-'temporarily anchor theshield to ythe pipe=section 161 by-wonnectin'g vthe shield with the stop165.` Such pins alsofallowthe pipe to be pushed into the well.-l Whenshield 6 is brought into position at the bottom'of therwell casing4, theweight of the column of pipe is easily suili'cient to break the pins.

It will be understoodfthatthe probing pipe may be entirely of flexibleor tlattened vor-elliptical sections or the vertical part ot" the pipemaybe-of standard pipe sections, only enough flattened or`llexiblersections being used at the lower end to provide-for thelateralprobing action. 1t will also be understood that the weight of thevertical column of pipe whichis -suspended inthe well by suitableraising and loweringmeans, as wellknown in the drilling art, providesthe necessary force for pushing out the laterally extending-probing endof thepipe This applies to the flattened or elliptical pipe, as well asto the commercial llexible -pipe `of thesform shown in Figure 1.

The use and operation of this invention insofar as the same have notheretofore been fully explained are as follows:

In general, the method -and apparatusshown herewith combine in their usethe steps of 'forming a drill hole, positioning a fixed casing in it,and positioning in it an indexing pipe or shield in combination with aflexible tool carrying tube. With these-parts in place, the rotatableassembly is rotated to the'desired position, the flexible tool carryingtube is lowered until thel tube is at or near the bottom of the desiredstratum,-and a liquid or a mixture of liquid is pumped throughthelllexible tube. Material which is beingrecovered then passes upwardlybetween the rotatable tube and the index pipe or casing and isdischarged into a suitable tank.

Considering the arrangement shown in'Fig. 1 with'the parts in theposition -which they occupy-in that ligure, water or other active liquidis pumped downwardly through the llexible pipe 14, is discharged throughthe tool and operates'the cutting members 86. At the same time air, gasor, any light inert iluid is pumped downwardly through the pipev system-20 (Fig. 3) and flows downwardly through pipe-14, and being Vlighterthan the active liquid lills the upper portion of the vcavity producedby the mining. The volume and pressure of this fluid determines thedegree to which the level of water within the working is raised orlowered. The liquid or solution passes upwardly between the indexingtube-6 and the pipe 14 within it. Fig. 8 indicates a substantialclearance between these members even at the lower end of the tube 6where the guiding members 51, 52 are positioned. The liquid raised fromthe well ows outwardly at the top of the indexing tube 6, thence intothe chamber 10a through the pipe 10b, shown in Fig. 1, and into the tank13. The annular space between the tube 6 and the casing 4 allordsinsulating means of great utility.- Fig. 1 shows an'accumulation oflight oil 12a between the wall 12 and the septum 13 and an opening 13afor the exit ofthe subnatant aqueous layer 13b. Where such a light oilis used as a filler, or inert protective medium, if it is'present insullicient quantities, it will appear at the location 12a. If the supplyin the well has become depleted, so that none of it is forced upwith-the solution, checking at this location will show that fact andadditional oil may be supplied.

In general, the freeing and removal of material from a well follows thesteps above described. For some purposes water alone is sutlicient toform a solution which then is carried to the surface. For other purposesand for other materials the water must be heated.` Similarly, manydili'erent materials may be used for maintaining the level of liquidwithin the working-space.' Airalone may suice. Liqnidssuch askeroseneand various otherhydrocarbons may be used. These liquids shouldbe such that they do not mix freely or form `a solution with the productwhich isbeng recovered. Of importance is the action of the solvent torelease oil from subterranean oilsand deposits wherebythe sand is leftbelow ground.

.In all of the variations of the method it is ordinarily preferable toremove the desirable material first, by dissolving or otherwise, fromthe lower portion of the stratumzin. which it appears. In the case ofsome materials, particularly where a solution is formecLit is sufficientto dissolve the material upwardly by controlling the operation bytheliquid jet and by controlling the level of liquid within the stratum byraising the tubet. A"this action is had by use of the jacks 8 of Fig. l,the tube 6 after raisv ing being cutoff to the level as shown in Fig. l.

,As the desirable stratum is removed, the level of liquid may be allowedto rise. -In the case of oil and other materials which are not trulydissolved from-their stratum, but are removed by hot water or otherwise,it may be necessary to raise the level of the working by introducingmaterial such as concrete. Sometimes alsov it is desirable to put downconcrete, asphalt or other material where the undesirable stratum belowthe desired stratum'is water soluble or water pervious or is of suchnature that it may be removed by thewater or other fluid which isintroduced into the well. Where this is the casea thin layer of theprotecting material will suflice. v

.The use of `air or gas intermingled with the Water which is forced outof the tool has been referred to. This may be supplied continuously oromitted entirely, or it may be supplied in charges. Thus, in effect achargeof compressed air or other gas may be shot at intervals throughthe flexible tube and this has the mechanical elect of stirring up thematerial within the well. -ltlmay have an almost explosive effect, ifthe gas is introduced at sufficient pressure. The air meter 31, shown inEig; 3, may include a timing device for giving different air or gascharges at regular intervals. Sometimes the air pressure within theflexible pipe 14 assists the pipe to lioat` somewhat,l for example inbrine. Because of this buoyancy and because of the fluctuation of theair or vgas charges,

thepipe itself may jump and thus tend to lessen the l friction of itupon the floor of the cavity.

The method is not dependent on the details of the apparatus but maybesomewhat varied by using different apparatus. t

Air, oil orother similar material is iloatedron the top of the liquidmass within the well.l This may be an oil which will not mix with thatwhich isA being extracted in the well with alighter oil to assist inextraction and f raising tothe surface of the ground. Causticsanddetergents may also be used :in connection with the oil removal fromthe stratum in which `it is found. Y

The embodiment of the invention as illustrated in Figs. 24 to 33 willnow bedescribed. As already mentioned, this method is particularlyapplicable `to removal of materials occurring in comparatively thinvstrata, and more especially materials soluble in water or aqueoussolutions, such as sodium sesquicarbonate (alsofknown as trona), sodiumchloride, etc.. Referring to Fig. 26, a vertical well 201 is drilleduntil-the-soluble stratum 202 has been penetrated, the end of thedrillhole beingshown at 203. The hole is preferably `provided with the usualcasing 204 in a manner well known in the art. The stratum having beenlocated, the cavity formed therein may be enlarged by the use of solventintroduced through a pipe 205 having branches 20,6, y:6'in 'accordancewith any of the methods disclosed i, herein. lThe solution formed isremoved upwardlyl throughv the annular space between the pipe 205 andcasing 204.

The stratum having been located by means of the well 201, a second well207 is commenced at a suitable distance therefrom. By the use of knowndirectional drilling methods, the second drill hole 207 is inclined orcurved so that it will intersect the stratum 202 at an angle enablingthe introduced pipe 208 to make the bend in the stratum without kinkingor straining the metal unduly. A casing 209 is provided which may reachto the soluble stratum. The end of pipe 208 may be advanced by a probingaction beyond the end of the casing 209 and caused to reach the cavitysurrounding the end of the pipe'206 and to thereby establishcommunication between the two holes. Pipe 208 is suitably provided withnozzle 2id. Nozzles 211 of suitable type may be provided for pipes 206,206. Soluble material is removed as already described in the case ofpipe 205. When communication between the two wells has been established,the exible pipes'208 and 205 may be withdrawn and solution introducedthrough casing 209 and removed through the casing 204. I The advantageof the inclined drill hole 207 will now be apparent. When communicationis establishedbetween the inclined hole 207 and the vertical hole 20L itwill be seen that the casing 209 for the inclined hole allows the pipe20S to be moved forward in the direction roughly determined by the lineconnecting the holes 207 and 201 at the surface and to continue for anindefinite distance beyond it.

Figures 24 and 27 illustrate an improved method of removing solublesfrom a comparatively thin stratum by utilizing' this' advantage of theinclined drill holes. In these figures, the stratum is represented toslope from the top toward the bottom of the ligure,A and from the rightto the left thereof. ln so proceeding, the region A at the top is iirstdrilled, preferably using the combination of the straight and inclineddrill holes as shown. Then, the region B vdownslope from region A isdrilled, preferably using the same combination of vertical and inclinedholes as illustrated. By methods already described, communication isestablished between region A 'and region B through the soluble stratum,enlargement of region taking place in the direction shownby thedottedlines 212 while region Bis similarly enlarged in the direction ofregion A, as shown by-dotted line 213, such action taking place untilthe cavities formed unite.'

lt is a feature of my 'invention that at this -point the operation offeeding solvent and removing solution by balancing thefpressures of thetwo columns of liquid may be discontinued and the hydrostatic pressureon the liquid in the two cavities'now united may be released. Thereby,the further ow from point A to point B, for example, will be by gravity,and of whatever volume desired. (Note that if the liquid were underhydrostatic pressure, it would of necessity ll the cavity except for thelayer of compressed air between the level of the liquid and the roof.)Discontinuance of the hydrostatic pressure condition has the furtheradvantage that should a break occur in the roof, the liquid will nolonger be forced into the new cavity formed. A still further advantageis that by employing restricted quantities of liquid owing through theunderground channels, the temperature of such liquid may be relativelyeasily coutrolled, whereby that temperature may be maintained f whichwithin limits will give the liquid the most dis- `series of contactsindicated diagrammatically at 213",

is provided, such that when the liquid is drawn down to the level of thelower set of contacts, the motor will be i7 stopped. This will preventracing when there is not suicient liquid for the pump to handle. Whenthe liquid level rises above this minimum to the upper set of contacts,the motor will be started and continue to operate the pump so long asthe desired level is maintained.

By maintaining the conditions described, the amount of liquid passedthrough the workings may be regulated and only a measured amount ofliquid introduced, if desired, The level of the liquid in theunderground passages may also be controlled. Also, the temperature ofthe liquid may be readily controlled. By regulating the rate of flow andthe temperature with respect to the distance between the inlet and exitwells, the degree of saturation of the liquid when it reaches the exitwell and in the vicinity of the pump in such well, may be controlled.The degree of saturation may be measured, for instance, at the dischargeof the liquid from the pump at 213i. (Fig. 33.) Obviously, the freshliquid near the inlet well will be most active and by permitting theliquid to become fully saturated before the exit well is reached and byproperly regulating the level of the liquid adjacent thereto, thedissolving of the soluble deposit under the roof of the working in thevicinity of the pump can be kept to a minimum. Thus, danger of caving ofthe roof, particularly of the shale or other material overlying thesoluble stratum, can be avoided. The pump can therefore be kept inoperation without interference from caving while large amounts of thesoluble material are removed at points remote from the pump.

Figures 28, 29 and 30 show how the free ilowing solvent tends todissolve out soluble material when the floor of the cavity 213E slopesto the left, as shown, thereby having the tendency to uncover more andmore of such oor by following such downward slope.

Communication having been established between wells A and B, well C isdrilled, such region being selected where the stratum therebeneath islower than at points A and B, such regions C, B and A forming a triangleas seen in Figs. 24 and 27. Communication is then established throughthe stratum between the points B and C. Solvent is then introducedthrough the pipe at A and removed from region C, preferably by means ofpump 2131, now placed in well C. In this manner, the entire cavity isenlarged by the action of the solvent introduced at A and flowing bygravity to region C. The dot and dash lines 214, 215 (Fig. 27) show theprogressive enlargement of the cavity. The action showncross-sectionally in Figs. 28, 29 and 30 already mentioned isaccentuated upon removing the solution from well C.

One advantage of my improved method is that should cave-ins occur, theyeffect no construction of the pipe, since none is there, and their chiefeffect is that material of the soluble stratum is loosened and broken upand is the more readily dissolved. Having formed a cavity, as shown inFig. 27, the process may then be repeated as desired and as permitted bythe extent of the stratum. Fig. .30 shows a sloping roof formed prior tosuch a cave-1n.

In mining by means of communicating vertical and clined wells, asdescribed in connection with Figs. 24 to 27, the driving of the verticalwell has usually been referred to as the first step. It is notnecessary, however, in all cases to drive the vertical wells iirst andin some instances the vertical well may be omitted altogether. Forexample, the inclined well may be put down iirst and the positionreached by its lower end determined by known well surveying methods. Thevertical well or a second inclined well may then be drilled, directed insuch a Way as to meet the bottom of the rst inclined well. Where aconsiderable cavity has been formed at the bottom of the first well orpair of wells, it is often possible to eiect a communication with suchcavities by the use of an inclined well alone. For example, in thesituation illustrated by the diagrams 24 and 26, if wells had beendrilled at regions A and B and brought into i8 connection, an inclinedwell only would'probably be needed in region C, in order to connect withthe channel already established between regions A and B. y

In Pig. 3l, the action is shown of an elastic pipe having an initial setas already described and illustrated in Fig. 15. Thus, drill hole 220having been made and casing 221 having been placed therein, a pipe 222,the end of which has been given an initial set to spring outward, isinserted. Upon emerging from the casing the end of the pipe which hasbeen restrained while within the casing is free to bend and thusacquires a lateral direction as shown. This method is applicable tostrata of somewhat greater thickness than illustrated in Figs. 24 and25, for example.

Fig. 32 shows the action of the pipe 222 after it has reached the floorof the cavity, as for example the shale or other rock constituting same,and the action of the solvent which is introduced through the pipe 222and nozzle 223, and is removed upwardly through the casing outside pipe222, this action continuing as indicated by the cavity there shown. Bythus always feeding the solvent `at ya point remote from the well andadjacent the receding wall of the cavity, the effect is had that thefresh solvent starts its greatest dissolving action immediately upon itsdischarge, thus producing a cavity having a substantial height 2231.

In the foregoing specification where reference is made to a probingnozzle, this may be either a separate nozzle formation attached to apipe (Figs. l, 18, 20) or it may be the pipe end itself so shaped yas todischarge a liquid under pressure at the end of the pipe, as, forinstance, by providing the end portion of the pipe with lateralperforations (Fig. 2l).

Where reference is made in the specification to an abutment contacted bythe end of a probing pipe, this may be al post as shown in connectionwith Figures l, l2, 13 and 14, or it may be an underlying resistantstratum as illustrated in Figures 24, 25, 26 and 32.

While I have described in detail certain preferred meth'- ods which Ihave found to be most desirable and efficient in practicing myinvention, and while I have illustrated and described in detail certainforms of apparatus which I have found well adapted to carry out therequired operations, I do not wish to be understood as limiting myselfto the performance of the process in the precise manner set forth or thefollowing of a particular sequence of operations where this is notessential to secure the intended result, or to the use `of theparticular apparat-us as set forth in the specification, as I realizethat changes both in procedure and in the apparatus are possible; and Ifurther intend each step or sequence of steps and each element `orinstrumentality appearing in .any of the following -claims to beunderstood to refer to all equivalent steps, sequences of steps,elements or instrumentalities for accomplishing substantially the sameresult in substantially the same `or equivalent manner.

I claim:

l. yIn 4the art of removing material from deposits thereof below thesurface of the earth, which material is capable of being removed by andcarried in a liquid vehicle, the method which consists in drilling awell into the deposit, passing therethrough a pipe which is relativelynon-flexible in one plane but is relatively freely bendable in a planeat right angles thereto, the end of said pipe being advanced until itsbottom contacts an abutment and is thereby deflected, causing the pipeto bend in the direction of its lesser bending resistance, passing aliquid therethrough, withdrawing the same laden with material from saiddeposit, and then continuing to advance the end of said pipe laterallyof the well axis as said material is removed, utilizing the relativelynonliexible characteristic of the pipe in the plane at right angles tothe direction of bend of the pipe to maintain the direction of advanceof the pipe laterally of the well axis the diameters of said Well andpipe being so related in size that va-,saaiiis the walls of the wellhold the pipe from bending be- -yond its elastic limit while passingthrough the well.

2., iln the art of subterranean mining of strata containingvalues whichmay be removed by the action of a liquid vehicle or solvent, the stepswhich consist in drillinga well into a stratum to be mined introducing acasing into the well as it is being drilled, passing a bendable probingpipe down said well through said casing, the inner diameter of saidcasing being suiiiciently close in size to the diameter of the probingpipe to hold the probing pipe against bending beyond its elastic limitwhile passing through the well the end of said probing pipe beingadvanced until its bottom contacts an abutment, causing the lower end ofsaid probing pipe to be laterally .diverted below the lower end of saidcasing. forcing liquid under presure through said pipe so as to form achannel in the stratum to be mined, forcibly advancing the pipe so as tocause the laterally diverted end thereof to advance through the channelin the stratum, and maintaining a rate of advance of the probing pipesuch that the channel is not enlarged by the iiow of the liquid duringthe advance of the pipe beyond a size where support suiiicient toprevent buckling of the pipe is aorded by engagement between the wallsof the channel and the advancing pipe. 3. In the art of subterraneanmining of strata containing values which may be removed by the action ofa liquid vehicle or solvent, the steps which consist in drilling a wellinto a stratum to be mined, passing a bendable probing pipe down saidwell and advancing the same until its bottom contacts an abutment and isdeflected laterally beyond the point where said well enters said stratumwhile forcing liquid under pressure through said probing pipe,maintaining the rate of lateral advance of said probing pipe through thestratum at such a value as to prevent enlargement of the passage formedby the probing pipe to an extent greater than that required to permitadvance until the probing pipe has been advanced laterally tosubstantially the maximum distance desired from the bottom of the well,and continuing the flow of liquid down said probing pipe whereby thematerial can be removed from the deposit near the end of the probingpipe at a greater rate than near the bottom of the well and .an enlargedcavity will be formed near the point of maximum advancement of theprobing pipe while the formation of an enlarged cavity adjacent to thebottom of the well is delayed.

4. In the art of subterranean mining of strata containing values whichmay be removed by the action of a f liquid vehicle or solvent whichstrata overlie a door stratum of more resistant material, the stepswhich consist in drilling a well deep enough to reach the stratumcontaining tlie values to be removed. passing a bendable probing pipedown said well until it engages the resistant oor under the stratum tobe mined,` continuing the ad- Vance of the probing pipe so as to causethe end thereof to be laterally diverted, forcibly advancing the pipe soas to cause the laterally diverted end thereof to slide outwardly alongthe surface of the underlying oor stratum, and forcing liquid underpressure out through said pipe so as to form a channel through the lowerpart of the stratum to be mined immediately above the surface of thetioor stratum.

5. In the art of removing material from deposits thereof below thesurface of the earth, which material is capable of being removed by andcarried in a liquid vehicle, the method which consists in passing astream of. said liquid through a well reaching into the deposit andcausing the stream of liquid to impinge against a wall of the formedcavity in the deposit, moving the point of discharge of said streamtoward said wall as the same recedes to maintain impingement upon saidwall, and introducing air intermittently into said stream ofliquid sothat the same will be released Vin bursts at the point of discharge of`said lstream adjacent to the wall so `as to 20 produce yagitationladjacent to the point of the liquid.

6. "In the art of mining material from deposits below the surface of theearth, which material is capable of being removed and carried in aliquid vehicle, themethod which consists inl sinking a drilled well toreach into the deposit, passing a iiattened pipe therethroughuntil 'itsbottom contacts an abutment and is thereby causedto bend in thedirection of the shorter axis of the atte'ned pipe section, laterallyinto the deposit below the point where the drilled well enters thedeposit to assume a di'- rection deviating laterally from the well axis,passing said liquid through said pipe and withdrawing the same ladenwith said material from said well. 1

7. in the art of mining material from a deposit below the surface of theearth, which material is capable of being removed through a drilled wellreaching said deposit, the steps which include locating a probing pipeguiding element near the bottom of the well, adjusting said probing pipeguiding element in azimuth, making a determination at the bottom of saidwell by means of known well surveying methods of said adjustment inazimuth, and passing down said well a flattened probing pipe easilybendable in a direction transverse to the longer cross-sectional axisand ditiicultly bendable'in a direction transverse to its shortercross-sectional laxis, the pipe being pre-bent for lateral extension inthe direction of its lesser bending resistance, and positioning saidprobing pipe in said Well so that bending in the direction transverse toits longer cross-sectional axis will take place in the predetermineddirection in azimuth.

8l The method of dissolving and removing' material from a subterraneanstratum which has a downward iuclination, which method comprises thefollowing steps: drilling a first well, thereby locating the stratum,drilling a second well downslope of the stratum from the rst well andestablishing communication between said Wells by passing a liquid intosaid wells and withdrawing solution therefrom, drilling an additionalwell or Wells to a point in said stratum where the same is lower than atthe points where the first and second wells are drilled,` suchadditional well or wells being at a substantial distance from the linejoining said first and second wells, establishing communication throughsaid stratum between the second and additional wells, and thenestablishing a flow of liquid by gravity which is introduced through therst well, and the resulting solution withdrawn through said additionalwell or wells.

9. The method of mining a subterranean stratum from which values are tobe extracted, said stratum overlying a tloor stratum of more resistantmaterial, which com,- prises irst drilling a generally vertical well todetermine the location of the stratum to be mined, introducing Aa liquidinto the well to enlarge the cavity at the bottom thereof, drilling aninclined well commencing at a point on the surface of the earth asubstantial distance from the start of said first well, directing thedrilling of said second well towards the cavity at the lower endl ofthe' rst well, passing a probing pipe down said second well beyond thelower end of said second well and advancing the same into said cavity,the inclination of said second well enabling the pipe to extend withoutexcessive bending along the oor of said stratum, introducing a hquidvehicle down said pipe, and removing the liquid vehicle with valuescarried thereby through said first well.

l0. The method of mining asubterranean stratum from which values are tobe extracted which comprises drilling a pair of spaced wells intothestratum, at least one 'of saidvwells being inclined so that the wellsare closer together at the bottom than at the top, passing a probingpipe down an inclined well, forcing liquid down said probing pipe, andadvancing said probingpipe ina lateral direction beyondthe bottom of thedrilled inclined-well until communication is established through saidstratuml from one well to the other.

impingement of

